Research is proposed to investigate the individual differences observed in spoken and printed word recognition by people with profound hearing impairments. The long-term aims of the research are to discover how the psycholinguistic processing system is affected by perceptual experience and to apply this knowledge to therapies involving sensory aids (i.e., cochlear implants, hearing aids, tactile aids) and communication strategies. Two studies are proposed that examine processing-channel (i.e., speech versus orthography) relationships during spoken and printed word recognition. Study I tests the hypothesis that phonological code in reading is a function of speechreading ability in individuals with perlingual profound hearing impairment. Experiments will employ lexical and semantic decision techniques to probe use of phonology. Study II tests the hypothesis that individuals who make use of phonological codes during printed word recognition can readily transfer their knowledge of printed words to recognition of spoken versions. Study II will employ a transfer task in which printed pseudo- words are learned in the first part of the procedure, followed by spoken pseudo-word learning. Transfer from printed to the spoken learning will be assessed. It is predicted that a distinct pattern of learning will be observed across participant groups. Participants in Studies I and II will be adults with normal hearing and adults with perlingual-onset profound hearing impairments. Direct comparisons will be made among three groups of adults with perlingual-onset, profound hearing impairments, those with: tested performance that is high for printed word vocabulary and high for speechreading ability (HPHS); High printed vocabulary and low speechreading (HPLS); and low printed word vocabulary and high speechreading (LPHS). Knowledge about the causes of individual differences can be employed to guide therapies involving sensory aids and communication strategies.